1. Field of the Invention
This invention relates to a data photographing system which, when pictures are taken by a camera, triggers an electronic flash to record data, such as memoranda, the date or the time, on the camera film.
2. Description of the Prior Art
The recent development of motor-driven camera systems has made popular continuous photography and remote photography. In these types of photography it is desirable that, in addition to the scene to be photographed, certain data, such as memoranda, the date or the time, also be recorded on the film.
Conventional devices for photographing such data have a pilot lamp which turns on when a capacitor has been charged up to the particular voltage level required to energize a flash tube which is provided for illuminating the data. The flash tube is energized in response to actuation of the shutter opening mechanism of the camera after turn-on of the pilot lamp has been confirmed by the photographer so that the data are photographed at the same brightness as that of the main scene which is recorded on the film frame. However, turn-on of the pilot lamp cannot be readily confirmed during remote photography. Moreover, when continuous photography is effected by means of a motor-driven device, confirmation of the turn-on of the pilot lamp is irrevelant because the picture-taking cycle is predetermined. If photography is effected prior to turn-on of the pilot lamp, the data will suffer from under-exposure as compared with the intensity of the main scene exposed film surface area.
When continuous photography is effected at a rate of several frames per second, the flash capacitor must be charged and discharged several times per second, which requires the power source to be of such large capacity that the data photographing apparatus is undesirable in terms of its portability. However, where the datum to be recorded is the time, time periods of 1 second or less are difficult to read whether the timepiece used is the three-hand analog display type or the digital display type. Therefore, when timepieces of these types are photographed, there is no practical advantage in photographing the time at a rate higher than one frame per second. Thus, it may be said that continuously varying data, such as the time, are recorded sufficiently for practical purposes if they are photographed on the film at a rate which enables clear identification of the variations in such data.